# iSTREEM® A Web

- based River Chemical Concentration Estimation Model
Dr. Xinhao Wang University of Cincinnati EPA Exposure Modeling Public Meeting March 19, 2013

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# Who are we?

The 120

- member trade association of the

$30 billion US cleaning products industry

2Onsite Treatment Municipal Waste Water Treatment Plants

Soils Surface waters Sludge Effluent Ground water

Drinking water Direct Discharge Household Wastewater 

# Fate of Consumer Product Ingredients

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# iSTREEM®

- What is it?

• Environmental exposure model for down

- the

drain consumer products

• Estimates chemical concentration in the effluent of >10,000 municipal WWTPs in the U.S.

• Estimates in

- stream concentrations for 30,000 effluent

- impacted perennial streams in the U.S.

• Estimates raw drinking water concentrations at surface water intakes ( ∼ 1,700)

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# Model Algorithm U.S. rivers are segmented, and modeled downstream flow

Losses within segment

• Biodegradation

• Downstream Transport

• Drinking water intake Sources to segment

• WWTP Effluent

• Upstream Input

• Tributary Input

• Industrial Loads WWTP Effluent Calculates effluent concentration Influent to WWTP (per capita use x population served)

Calculates concentration at drinking water intake Calculates concentration for effluent

- impacted streams



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# User Inputs

• Chemical per capita use rate (national or regional)

• Chemical fate parameters

– Primary treatment efficiency

– Secondary treatment efficiency (activated sludge, lagoon, oxidation ditch, RBC , trickling filter)

– In

- stream loss (first order)



# • Geographic scope ( national or regional )

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# Chemical Fate Parameters

In

- stream 1 st order loss (e.g., sorption, biodegradation, etc.) 

### Secondary treatment

Present Pop = 2004, Future Pop = 2008 Mean River Flow or Low Flow (7Q10, worse

- case , sometimes 100% effluent)

# U.S. EPA Data Sets

• Enhanced

- River Reach File 1

– 1:500,000 scale; Contains stream data such as reach number, type, name, length, slope, annual/monthly mean and low flows and flow velocities

• Reach File 3 and National Hydrography Dataset (NHD+)

– 1:100,000 scale, used initially to locate WWTPs on RF1 reach

• Clean Watersheds Needs Survey

– WWTP data includes NPDES permit numbers, treatment type information, population data, effluent flow, and location data for 2008

• Drinking Water Supply File

– Contains data for U.S. drinking water facilities: Includes facility code, production volumes, population served, and locations for plant intakes and sources (SDWIS

– 2004), also found in BASINS model

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# Wastewater Treatment Plants

Type Description Count % Pop. % Flow
S Activated Sludge 4,866 79.4% 81.1%
L Lagoon 3,360 6.2% 5.9%
O Oxidation Ditch 1,052 5.8% 4.9%
F Trickling Filter 802 6.7% 6.3%
R Rotating Biological Contactor 319 1.9% 1.8%
P Primary 15 0.01% 0.01%
Total Public WWTPs in US 10,414 100% 100% (US EPA Clean Watersheds Needs Survey

– 2008)



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# Three

- Panel Main User Interface

Map Display Window Operation Panel Map Control

Panel Navigation bar(Comparison of predicted to observed response yields ratios ranging from 0.53

- 1.25) 

# Model Verification

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# Model Verification

1

2

3

4

5

6 Minneapolis

Moline

St. Louis

Memphis

Baton Rouge New Orleans 

# Model Verification (cont.)

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# Model Verification (cont.)

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# Model Results

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# View of Model Results

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# Comparing Model Simulations to Regulatory and Effects Thresholds

• Compare iSTREEM® effluent predictions to Oregon DEQ plant initiation levels under their Priority Persistent Pollutant program
o Triclosan: 70 ug/L



### • Compare iSTREEM® in

- stream predictions to effects threshold

o HC5 for Triclosan: 0.8 ug/L for aquatic species (Capdevielle et al., 2008)

o EU PNEC for DEET: 43 ug/L for freshwater aquatic species (EU Assessment Report, 2010)



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# National Simulation Parameters

Ingredient Triclosan 1 LAS 1 AE 1 AES 1 DEET 2 Oxidation Ditch 95 99 99 98 56.9 Activated Sludge 95 99 99 98 56.9 Lagoon 95 98 99 98 56.9 Trickling Filter 80 80 96 93 56.9 Rotating Biological Contactor 95 98 99 98 56.9 Primary 30 27 18.9 0 0 Decay (d

- 1 ) 0.264 0.7 31.2 24 0.0234 River Temperature 20 20 20 20 20 Scenario Present Pop Present Pop Present Pop Present Pop Present Pop National Loading factor (g/capita/day) 0.0062 3.1365 1.4675 2.7708 0.0241

1 De Zwart, D., S.D . Dyer, L. Posthuma , C.P . Hawkins. 2006. Use of predictive models to attribute potential effects of mixture toxicity and habitat alteration on the biological condition of fish assemblages. Ecol. Applications 16 : 1295

- 1310.

2 Aronson, D., J. Weeks, B. Meylan , P.D. Guiney, P.H. Howard. 2012. Environmental release, environmental concentrations and ecological risk of N,N

- diethyl

- m - toluamide (DEET). Integr . Environ. Assess. Manag . 8: 135

- 166.



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# Triclosan concentration in effluent

0% 20% 40% 60% 80% 100%

0.01 0.1 1 10 100Cumulative Percentage of Facilities

Log Concentration (ug/L)
National effluent-simulated Measured effluent Oregon DEQ initiation level/detection limit (70 ug/L)



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# Predicted In

- stream Concentration: Triclosan

0% 20% 40% 60% 80% 100%

0.001 0.01 0.1 1 10Cumulative Percentage River Reaches

Log Concentration (ug/L) HC5 for Triclosan (0.8 ug/L) Low flow (7Q10) Mean flow



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# DEET concentration in effluent

0% 20% 40% 60% 80% 100%

0.1 1 10 100Cumulative Percentage of Facilities

Log concentration (ug/L)
National effluent-simulated Measured data Observed effluent concentrations (from Aronson et al., 2012)



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# Predicted In

- stream Concentration: DEET

0% 20% 40% 60% 80% 100%

0.01 0.1 1 10 100Cumulative Percentage River Reaches

Log Concentration (ug/L) PNEC for DEET (4 3 ug/L) Low flow (7Q10) Mean flow Observed surface water concentrations (from Aronson et al., 2012)



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# Conclusions

• iSTREEM® provides ability to predict in

- stream concentrations of user

- defined chemicals on a national scale or a watershed scale

• Model verified for broadly discharged chemical

• GIS/Internet platform enables universal access to exposure model, ease

- of

- use

• GIS functionality

- spatially

- varied input, analysis on variety of scales (e.g. watershed/regional/national) lends to new insights

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# For More Informatio n

• Go to the ACI Science website: http:// www.aciscience.org/iSTREEM.aspx

• Log in to iSTREEM ® directly: http :// gis2.uc.edu/iSTREEM

References Wang et al. 2005. A river water quality model integrated with a web

- based geographic information system. J. Environ. Mgmt. , 75: 219

- 228

. Wang et al. 2000. GIS

- ROUT: a river model for watershed planning. Environment and Planning B: Planning and Design , Vol 27(2): 231

– 246.



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# Contact Information

Dr. Xinhao Wang Schools of Planning University of Cincinnati Cincinnati , OH 45221
- 0016 513
- 556
- 0497 xinhao.wang@uc.edu

Dr . Paul C. DeLeo American Cleaning Institute 1331 L Street, N.W., Suite 650 Washington, D.C. 20005 202
- 662
- 2516 pdeleo@cleaninginstitute.org 

# http://www.aciscience.org

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